1. Field of the Invention
The invention relates generally to seismic energy vibrator carriers and support systems and, more particularly, but not by way of limitation, it relates to an improved truck-mounted shear wave vibrational seismic energy transducer.
2. Description of the Prior Art
The prior art includes several types of carrier mounting configurations which provide seismic energy coupling to the earth's surface with requisite high efficiency. The prior carrier-mounted vibrators of the shear wave transducer type are particularly characterized in the prior art by U.S. Pat. Nos. 3,205,971; 3,353,772; 3,372,770; and 3,690,402. The U.S. Pat. No. 3,205,971 deals with a prior apparatus wherein vertical air springs and lateral coil springs were utilized to couple a shear wave vibrator, as directly supported, to opposite-side support columns operative to suspend the vibrator assembly beneath a carrier. Yet another form of suspension apparatus is illustrated in U.S. Pat. No. 3,353,772 wherein a shear wave vibrator is suspended from a carrier with vertical columns supporting over the vibrator base plate by means of vertical air bags, and adjustable tension leaf springs having slide-guide contact with the vibrator assembly are utilized to provide lateral stabilization. The extremely high lateral spring tension required in this scheme resulted in reduced isolation of the base plate lateral motion relative to the carrier vehicle. This stabilization problem was overcome to some degree utilizing a hydraulically-actuated lateral cleating arrangement as taught by the U.S. Pat. No. 3,372,770; and, still other attempts at adequate vibration isolation versus assembly stability were made with apparatus as taught in U.S. Pat. No. 3,690,402. It should be apparent from an inspection of these teachings that they are diverse in approach and, while each could be attributed certain attributes, there were attendant drawbacks which impose specific limitations of usage as were to be overcome by such as the present invention.